Oral Presentation Society for Molecular Biology and Evolution Conference 2016

Speciation and domestication in the zebra finch, an avian model system for evolutionary genomics (#46)

Christopher Balakrishnan 1 , Allison Lansverk 1 , John Davidson 1 , Simon Griffith 2
  1. East Carolina University, Greenville, NORTH CAROLINA, United States
  2. Macquarie University, Sydney, NSW, Australia

Zebra finches, native to Australia, have long been an important model system across a diversity of fields. Due especially to their role as a model for the study of vocal learning, the zebra finch was the second bird species with a completely sequenced genome. Zebra finches, however, also have tremendous potential as a model system for evolutionary genomics. Such a model is important in part due to the unique features of birds including their unusually stable karyotype and recombination landscapes, and their apparent slow evolution of postzygotic reproductive isolation. I will highlight our progress in two areas: 1) describing patterns of genomic variation among wild and domesticated zebra finches and 2) improving our understanding of gene regulatory evolution in birds. Despite the role of domesticated zebra finches in research, little is known about how domestication has influenced patterns of morphological and genetic variation. Domesticated populations are of interest because they often differ from wild populations in predictable ways, and domestication itself may influence the behaviors that are under study. To quantify patterns of divergence, we sequenced whole genomes of wild and domesticated zebra finches at medium depth (~8x). As expected, we find significant reductions in genetic diversity in domesticated populations. We also use multiple lines evidence to identify putative regions of the genome that have experienced selection during domestication. In addition to surveying genetic variation, we have also used RNA-seq to characterize brain gene expression divergence between two zebra finch subspecies that have been geographically isolated for over one million years. In contrast to many previously examined systems, we find that gene misexpression, indicative of potential Dobzhansky-Muller incompatibilities, is relatively rare. Like previous studies in other systems, we also find that regulatory divergence has occurred predominantly in cis regulation. Thus, these findings highlight both shared and unique features of avian regulatory evolution.